The present invention relates to collet tools, and more particularly to a hand held collet tool capable of removing and inserting collets into a circumferential retainer.
Collets are typically used in conjunction with chucks to hold tools such as drill bits, etc. Most single angled collets have a tendency to stick in the chuck. This is because the tapered angle of the collet is usually so shallow that the collets stick in the chuck after the clamping force has been removed. In order to change collets, there is a need to overcome this "self sticking" tendency and pull the collet from the chuck. To accomplish this, some collets are designed such that their forward end portion can be confined within a retainer, typically referred to as a nose piece. To confine the forward end portion of the collet within a nose piece, it is accepted practice to form a circular retaining ring about the forward end of the collet and provide a circular groove within the nose piece for receiving and retaining the retaining ring formed about the collet. Thus, when the nose piece is secured to the collet, the collet can be easily pulled from the chuck.
The problem now becomes one of removing and re-inserting a collet within the nose piece. This is often a very difficult and frustrating exercise, not to mention the potential damage that can be done to the collet and nose piece in the process. For example, it is not uncommon for an individual attempting to remove a collet from a nose piece to apply a side force to the rear or free end of the collet. In applying the side force attempting to pull the collet from the nose piece, it is very easy to mar the collet by impacting the collet with the sharp thread forms of the nose piece. Beyond that, by attempting to remove the collet by applying side forces produces very asymmetric stresses on the collet which is a precision device that needs to be treated and handled with care at all times.
There are collet removal tools commercially available. For example, Sandvik offers a ring type collet removal tool. Essentially, this device is nothing more than a ring designed to be inserted over the free or tapered end of the collet. By moving the ring toward the opposite end of the collet, the collet is compressed such that it can be removed from its associated nose piece. The ring type collet tool has a number of shortcomings. First, it is difficult to press a ring type collet tool over a collet, especially if the resistance to compression is substantial. Beyond that, there is no easy and convenient way to eject the collet from the ring once it has been lodged within the ring tool. Again, this problem becomes of greater concern when the collet is tightly held within the tool.
Therefore, there is and continues to be a need for a simple collet handling tool that is capable of both removing a collet from a nose piece and re-inserting the collet into the nose piece.